KR20190064304A - Polyester resin with improved heat resistance - Google Patents

Abstract

More particularly, the present invention relates to a polyester resin including a dicarboxylic acid compound, a diol compound, and a cyclohexyl bisphenol compound and having improved heat resistance and oxygen barrier property.
According to the present invention, it is possible to copolymerize a dicarboxylic acid compound, a diol compound, and a cyclohexyl bisphenol compound at a constant ratio, thereby exhibiting a gas barrier property similar to that of polyethylene isophthalate, A crystalline polyester resin can be produced.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a polyester resin having improved heat resistance,

The present invention relates to a polyester resin having improved heat resistance, and more particularly, to a polyester resin having improved heat resistance and oxygen barrier property, prepared by esterification reaction and polycondensation of a diol compound containing a dicarboxylic acid compound and a cyclohexyl bisphenol compound, Ester resin.

Polyethylene terephthalate (PET) is a polymer produced through condensation polymerization through esterification reaction of terephthalic acid (TPA) or dimethyl terephthalate (DMT) and ethylene glycol (EG) as main materials and has excellent physical properties, processability and economical efficiency. It is environmentally friendly and is used in a wide range of fields such as food and beverage containers and packaging materials, textiles for clothing, film and other fields.

However, the profitability of general-purpose PET continues to decline due to oversupply, and the need to develop high-value-added PET is highlighted. Accordingly, various products have been developed to control the crystallization rate and crystallinity of PET to change the processability, transparency, and mechanical strength of the final product.

Amorphous PET is a product group that can be applied to thick sheets, transparent containers for replacing glass, and large capacity containers by lowering crystallinity compared to conventional PET and increasing melt tension. It has the advantage of being a highly transparent PET copolymer free of haze during processing. As a method of lowering the crystallinity, DMT or TPA, which is one of monomers used in PET polymerization, is substituted with Diacid or Diacidester, or EG is substituted with 1,4-cyclohexane dimethanol (1,4 -CHDM), and other co-monomers are applied to PET. However, since the molded product has high transparency, it is difficult to obtain a high viscosity because it can not perform solid state polymerization for crystallization, and the gas barrier properties such as oxygen and carbon dioxide are lower than that of conventional polyethylene terephthalate.

In order to overcome the problems of amorphous PET, DMT or TPA is partially replaced with isophthalic acid (IPA). However, amorphous PEIT has been developed for the development of amorphous PEIT. However, The glass transition temperature (Tg) is lower than that of the conventional polyethylene terephthalate, which makes it difficult to process the product. In addition, there is a problem that a cyclic compound such as a cyclic dimer stable in a steric structure during the polymerization reaction is produced as a side reaction, thereby lowering transparency, productivity, and processability.

U.S. Patent No. 5,565,545 discloses a method of copolymerizing 10% by weight of comonomer isophthalic acid (IPA) or 5% by weight of 1,4-cyclohexanedimethanol (CHDM) as a main component of monomeric TPA and EG, To 350 ppm. However, as the content of comonomer IPA and CHDM increases, there is a problem of difficulty in solid phase polymerization due to lowering of melting point and lowering of heat resistance.

United States Patent No. 4,424,337 discloses a method for producing polyethylene isophthalate using sulfuric acid as a polymerization catalyst. Depending on the method of preparation, the cyclic dimer content in the polyethylene isophthalate can be greatly reduced. However, there is a problem that the use of sulfuric acid as a catalyst makes it difficult to operate a polymerization process such as corrosion of process equipment due to its strong corrosiveness.

Disclosure of the Invention The present invention has been conceived to solve the above-mentioned problems. It is an object of the present invention to provide a process for producing dimethicone (IPA) And to provide a novel polyester resin which prevents the dimer formation and the glass transition temperature from being lowered by applying a stiff heat-resistant monomer.

In order to solve the above-mentioned problems, the present invention relates to a process for producing a diol compound comprising 10 to 50 mol% of a dicarboxylic acid compound containing 5 to 40 mol% of isophthalic acid and a cyclohexyl bisphenol compound, The present invention provides a polyester resin produced by reacting a polyester resin with a polyester resin.

And a molar ratio of the diol compound to the dicarboxylic acid compound is 1 to 1.4.

The dicarboxylic acid compound may be at least one selected from the group consisting of phthalic acid, terephthalic acid, dibromoisophthalic acid, sodium sulfoisophthalate, phenylenedioxydicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-di 4,4'-diphenyl ketone dicarboxylic acid, 4,4'-diphenoxyethane dicarboxylic acid, 4,4'-diphenyl sulfone dicarboxylic acid, and 2, Naphthalene dicarboxylic acid, and 6-naphthalene dicarboxylic acid,

The diol compound is at least one selected from the group consisting of monoethylene glycol, diethylene glycol, 1,3-propylene diol, 1,4-butylene diol, 1,4-cyclohexane dimethanol and neopentyl glycol Based on the weight of the polyester resin.

And the cyclohexyl bisphenol compound is dimethyl cyclohexyl bisphenol (DMBPC).

And the polyester resin has an oxygen permeability of not more than 4 (cc · mm / [m 2 · atm · day]) evaluated according to the following method, and a glass transition temperature of 65 ° C. or higher.

According to the present invention, a copolymer of a dicarboxylic acid compound and a diol compound containing a cyclohexyl bisphenol compound is copolymerized at a given ratio to exhibit a gas barrier property similar to that of polyethylene isophthalate, It is possible to produce a low crystalline polyester resin.

Hereinafter, preferred embodiments of the present invention will be described in detail. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Throughout the specification, when an element is referred to as "including " an element, it means that it can include other elements, not excluding other elements, unless specifically stated otherwise.

The present invention relates to a polyester produced by an esterification reaction and a polycondensation reaction of a diol compound containing 10 to 50 mol% of a dicarboxylic acid compound containing 5 to 40 mol% of isophthalic acid and a cyclohexyl bisphenol compound Resin.

The polyester resin according to the present invention is composed of a dicarboxylic acid compound and a diol compound as main raw materials.

The dicarboxylic acid compound may include an aromatic molecule as a main component of a diacid compound. In the present invention, the dicarboxylic acid compound is not limited to phthalic acid, terephthalic acid, dibromoisophthalic acid, sodium sulfoisophthalate, Dicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletridicarboxylic acid, 4,4'-diphenyl ketone dicarboxylic acid, 4,4'-diphe 4,4'-diphenylsulfone dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, and the like, preferably terephthalic acid and / or another dicarboxylic acid compound Mixtures may be used. When the mixture is used, the content of the terephthalic acid in the total dicarboxylic acid compound may be 60 to 95 mol%, preferably 65 to 90 mol%, and most preferably 70 to 85 mol% . At this time, the isophthalic acid contained in the dicarboxylic acid compound may be contained in an amount of 5 to 40 mol%, preferably 10 to 35 mol%, and most preferably 15 to 30 mol% in the total dicarboxylic acid compound Mol%. ≪ / RTI >

The diol compounds include cyclohexyl bisphenol compounds and other diol compounds, including but not limited to monoethylene glycol, diethylene glycol, 1,3-propylene diol, 1,4-butylene diol, 1,4- Cyclohexane dimethanol, neopentyl glycol and the like can be used, and a mixture of monoethylene glycol alone, monoethylene glycol or diethylene glycol and / or other diol compounds can be used. Preferably, the diol compound other than the cyclohexyl bisphenol compound may be monoethylene glycol.

In the present invention, the cyclohexyl-based bisphenol compound contributes to the improvement of the heat resistance of the polyester resin, and has an effect of preventing dimer from being produced as a by-product in the production process. In the present invention, the type of the cyclohexyl bisphenol compound is not particularly limited, but it may preferably be dimethyl cyclohexyl bisphenol (DMBPC).

In the present invention, the content ratio of the diol compound to the dicarboxylic acid compound may be 1.0 to 1.4 on a molar basis. At this time, in order to improve the heat resistance, the intrinsic viscosity and the oxygen permeability of the polyester resin according to the present invention, the content ratio is preferably 1.1 to 1.3.

In the present invention, the cyclohexyl bisphenol compound may be contained in the diol compound in an amount of 10 to 50 mol%, preferably 15 to 45 mol%, and most preferably 20 to 40 mol%. If the content of the cyclohexyl bisphenol compound contained in the diol compound is less than 10 mol%, the improvement in heat resistance of the polyester resin may not be exhibited. If the content is more than 50 mol%, the intrinsic viscosity of the polyester resin is excessively increased, It may not be desirable from a gender perspective.

In the present invention, the temperature of the esterification reaction for producing the polyester resin may be from 170 to 300, preferably from 250 to 270, and preferably from 0 to 5.0 kg / cm 2, preferably from 1 to 3.0 kg / Can be performed. At this time, if the reaction temperature is too low, the reaction becomes slow. If the reaction temperature is too high, it is possible to cause yellowing of the product in the condensation polymerization step due to heat side reaction, so it is preferable to prepare the oligomer in the above temperature range.

The catalyst used in the esterification reaction may be a titanium compound, a magnesium compound, a germanium compound, and an antimony compound, which are conventionally used as a catalyst for polyester polymerization. However, considering the environmentally friendly and economical aspect, A titanium-based compound and a mixture of two or more of the above compounds may be used.

The amount of the catalyst is preferably such that the total content of the metal contained in the catalyst is 10 to 300 ppm, preferably 10 to 250 ppm, and more preferably 10 to 150 ppm, based on the weight of the finally produced polyester can do.

The esterification reaction of the diol compound including the dicarboxylic acid compound and the cyclohexyl bisphenol compound followed by condensation polymerization according to the above method may be carried out by transferring the ester oligomer produced through the esterification reaction to the condensation polymerization reactor It is preferable to increase the reaction temperature to near the melting temperature of the final resin and lower the pressure gradually to 1 torr or less over 1 hour.

The polycondensation temperature can be carried out by reacting at a temperature higher than the esterification reaction temperature by 10 to 40, preferably 15 to 25. When the condensation polymerization temperature is lower than 10, the reaction time becomes longer and the polyester forming the low molecular weight can be formed. On the other hand, when the condensation temperature is excessively higher than 40, side reactions such as thermal decomposition and coloring occur, It is desirable to maintain the range.

The polycondensation of the esterification reaction product may be carried out at a reduced pressure of 50 to 0.1 Torr, preferably 30 to 0.1 Torr, for 2 to 5 hours. By-products generated during the reaction under such reduced pressure conditions can be sufficiently removed from the reaction system.

According to an embodiment of the present invention, a phosphorus-based thermal stabilizer may be used in the synthesis of the polyester resin. Specifically, the phosphorus-based thermal stabilizer may be added to the esterification reaction or the polycondensation reaction.

Specific examples of the phosphorus-containing thermal stabilizer include phosphoric acid, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, triethyl phosphonoacetate, A mixture of two or more species may be used.

In addition, in the process of synthesizing the polyester resin according to the present invention, a cobalt compound may be further added to improve the color when producing the polyester resin. Examples of the coloring agent include cobalt acetate, cobalt acetylacetonate, cobalt benzoylacetonate, cobalt hydroxide, cobalt bromide, cobalt chloride (cobalt acetate), cobalt acetate, Cobalt chloride, cobalt iodide, cobalt fluoride, cobalt cyanide, cobalt nitrate, cobalt sulfate, cobalt selenide, and the like. ), Cobalt phosphate, cobalt oxide, cobalt thiocyanate, or cobalt propionate, but are not limited to, cobalt phosphate, cobalt phosphate, cobalt phosphate, Do not. The amount of the colorant added may be 10 to 40 ppm, and preferably 25 to 35 ppm, of the cobalt element content based on the polyester. If the content of the cobalt compound is less than 10 ppm, the color b value can be increased. If the content of the cobalt compound is more than 40 ppm, the production cost may be disadvantageous, and the color may darken. Although not limited to these cobalt compounds, it is preferred to use cobalt acetate.

In the present invention, the polyester resin may have an intrinsic viscosity of 0.5 to 2.0 dl / g, preferably 0.7 to 1.8 dl / g. If the intrinsic viscosity is less than 0.5 dl / g, it is not preferable because the mechanical strength is insufficient during injection molding of the film or sheet, which is difficult to use for various purposes.

The polyester resin of the present invention may have an oxygen permeability of 4 cc / mm / [m 2 · atm · day] or less (ASTM D3985) and a glass transition temperature of 65 ° C or higher, The glass transition temperature may be not less than 70 ° C, and most preferably not more than 2 (cc · mm / [m 2 · atm · day]), The glass transition temperature may be 75 캜 or higher.

The content of the cyclic dimer in the final polyester resin may be 5 wt% or less, preferably 3 wt% or less, and most preferably 2 wt% or less.

Hereinafter, a specific embodiment of the present invention will be described.

Examples and Comparative Examples

A dicarboxylic acid in which terephthalic acid (TPA) and isophthalic acid (IPA) were mixed in a ratio according to the following Table 1 was prepared and a diol prepared by mixing ethylene glycol and dimethylcyclohexyl bisphenol (DMBPC) was prepared and mixed at a molar ratio of 1: 1.2 Respectively. The slurry obtained by mixing the dicarboxylic acid and the diol was subjected to an esterification reaction at 260. The prepared oligomer mixture was transferred to a condensation polymerization reactor, and the reaction was carried out while gradually reducing the pressure to 1 Torr or less over 1 hour to raise the temperature up to 280 and to remove the low-molecular weight by-products resulting from the condensation. The polycondensation reaction was completed at a point where the viscosity was rapidly increased to prepare a polyester polymer.

Experimental Example

The physical properties of the polyester resin prepared in the above Examples and Comparative Examples were evaluated according to the following methods, and the results are shown in Table 1.

(1) intrinsic viscosity

The polyester resin prepared in the above manner was dissolved in a solution containing 60% by weight of phenol and 40% by weight of 1,1,2,2-tetrachloroethane at a concentration of 0.5%, and then the mixture was melt-kneaded at 30% by using a Cannon- Ubbelohde microviscometer Intrinsic viscosity (IV) was measured.

(2) Glass transition temperature

The glass transition temperature was measured using a differential scanning calorimeter (DSC) (TA instrument). The sample was heated from 20 to 300 ° C, quenched for 5 minutes, quenched, heated again at 10 ° C / min, and then the glass transition temperature and melting point were checked.

(3) Oxygen permeability

The oxygen permeability of the polyester polymer was measured according to Test Method ASTM D3985.

(4) Cyclic dimer content

After the polyester polymer was dissolved in a mixture of trifluoroacetic acid and deuterated chloroform, the cyclic dimer content was measured using a 1 H-NMR machine

[Table 1]

Referring to Table 1 above, it can be confirmed that the polyester resin containing the dicarboxylic acid compound, the diol compound and the cyclohexyl bisphenol compound (Examples 1 to 4) exhibits excellent gas barrier properties and improved heat resistance.

Particularly, in the case of Example 1, the glass transition temperature of the synthesized polyester was markedly higher than that of Comparative Example 3 in which DMBPC was not used as a comonomer, which indicates that the heat resistance was improved. Compared with the comparative example 3, the cyclic dimer content was decreased while the gas barrier property was maintained. It can be seen from this that, in the case of using the comonomer DMBPC in polyester synthesis, the physical properties of the polymerized polyester can be improved by increasing the glass transition temperature and decreasing the cyclic dimer content while maintaining gas barrier properties.

 On the other hand, in the case of Example 2, the content of comonomer DMBPC was increased to 40 mol% under the condition of the content of Example 1, and as a result, the content of cyclic dimer decreased compared to Example 1, 2.

On the other hand, in the case of Example 3, the comonomer IPA content was reduced to 15 mol% in the component content conditions of Examples 1 and 2. As a result, the glass transition temperature was increased and the cyclic dimer content was increased Respectively.

In the case of Example 4, it was confirmed that the gas barrier property was slightly lower than those of Examples 1 to 3, but it was found to be superior to Comparative Example 1 as a result of not coaction of the comonomer IPA under the component content conditions of Example 3, It was confirmed that the heat resistance was further increased.

 The oxygen permeability is a measure of gas barrier property, which is a measure of the degree of gas barrier property, which is indicative of the extent to which corruption or alteration of contents in a food container sensitive to gas permeability is caused. The oxygen permeability of polyethylene isophthalate, 1.5 (cc · mm / m 2 · atm · day).

 Therefore, the polyester resin according to the present invention can provide a polyester having improved transparency at the time of molding by suppressing the generation of reactants in the cyclic dimer portion while improving the heat resistance while maintaining a certain level of oxygen permeability. Therefore, Suitable for containers.

The preferred embodiments of the present invention have been described in detail above. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning, range, and equivalence of the claims are included in the scope of the present invention Should be interpreted.

Claims (5)

A polyester resin comprising a dicarboxylic acid compound containing 5 to 40 mol% of isophthalic acid and 10 to 50 mol% of cyclohexyl type bisphenol compound, wherein the diol compound is subjected to an esterification reaction and a polycondensation reaction. The method according to claim 1,
Wherein the molar ratio of the diol compound to the dicarboxylic acid compound is 1 to 1.4. The method according to claim 1,
The dicarboxylic acid compound is preferably selected from the group consisting of phthalic acid, terephthalic acid, dibromoisophthalic acid, sodium sulfoisophthalate, phenylenedioxydicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyl 4,4'-diphenyl ketone dicarboxylic acid, 4,4'-diphenoxy ethane dicarboxylic acid, 4,4'-diphenyl sulfone dicarboxylic acid, and 2,6 -Naphthalene dicarboxylic acid, and at least one member selected from the group consisting of
The diol compound is at least one selected from the group consisting of monoethylene glycol, diethylene glycol, 1,3-propylene diol, 1,4-butylene diol, 1,4-cyclohexane dimethanol and neopentyl glycol Lt; / RTI > The method according to claim 1,
Wherein the cyclohexyl bisphenol compound is dimethyl cyclohexyl bisphenol (DMBPC). The method according to claim 1,
Wherein the polyester resin has an oxygen permeability of 4 cc mm / [m 2 · atm · day] or less (ASTM D3985) and a glass transition temperature of 65 ° C or more.